Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
Visible Content: Not Found The requested URL /.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de was not found on this server. Apache Server at polaarenergy.com Port 80
Visible Content: Not Found The requested URL /.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de was not found on this server. Apache Server at www.polaarenergy.com Port 80
The /.well-known/acme-challenge/random-filename answers with the expected http status 404 - Not Found.
But: Plesk is a closed world. So it should work.
If it doesn't work -> ask your hoster.
One thing is curious: Your http + / sends:
X-Powered-By: PleskLin
But /.well-known/acme-challenge doesn't send that header, instead, there is the standard Apache "Not Found" message.
Do you have added additional definitions Plesk doesn't understand?
Or your hoster catches /.well-known/acme-challenge, so this Plesk-Header isn't sent.
If the server contains custom rewrite rules, disable them by renaming .htaccess file or web.config . Also, remove custom rewrite rules from Plesk > Domains > example.com > Apache & nginx settings .
and
Make sure that the Run the website in compatibility mode for the legacy option "Separate SSL/TLS and non-SSL/TLS content Plesk > Domains > example.com > DNS Settings option is not enabled in Plesk > Tools & Settings > Domains > example.com > Hosting Settings